A daylight lamp, also called a fluorescent lamp, a sun lamp, or a fluorescent light, is a lighting apparatus. It belongs to a kind of arc light and uses electric power to stimulate mercury vapor in argon or neon ambient for forming plasma and emitting ultraviolet light having a short wavelength. After the ultraviolet light is absorbed by phosphorus, the phosphorus will emit visible light for lighting. The light emitted in this method is fluorescent light.
Take a general fluorescent tube for example. A closed fluorescent tube is filled with low-pressure argon or argon-neon mixture gas and mercury gas. The inner surface of the glass fluorescent tube is coated with phosphorus fluorescent paint. Tungsten filament coils are disposed on both ends of the fluorescent tube. When the power is turned on, the current first passes through the filament for heating and electrons are released. The electrons will transform the gases inside the tube into plasma and amplify the current therein. When the voltage across the two filament sets exceeds a certain value, the fluorescent tube starts to discharge, enabling the mercury vapor to emit ultraviolet light with wavelengths of 253.7 nm and 185 nm. The phosphorus fluorescent paint on the inner surface of the fluorescent tube can absorb the ultraviolet light and emit visible light with longer wavelengths. The color of the emitted light is controlled by the proportion of the phosphorus. The adoption of the glass tube is to avoid leakage of hazardous ultraviolet light and other harmful materials such as mercury.
In the fabrication of lamps according to the prior art, electrode members are disposed on both ends of a fluorescent tube. Inside the fluorescent tube, it is a closed space. The gas inside the closed space is pumped out to make it in the vacuum state. Then the required gas, such as argon or argon-neon mixture gas and mercury gas, is added. The electrodes are fixed inside the fluorescent tube at both ends and used for sealing this fluorescent tube and forming a closed space. Then glue is coated inside the tube before fixing the electrodes at both ends. Nonetheless, the difficult part of this technology is that the glue coated inside the tube tends to flow into the closed spaced of the fluorescent tube and is mixed with the gases therein. This affects the light-emitting efficiency of the lamp.
Furthermore, in order to improve the above problem, electrode members are disposed on both ends outside a fluorescent tube. Glass rings are disposed between the electrode members and the fluorescent tube and used for fixing and sealing the gaps therebetween. Nonetheless, due to the difference in thermal expansion coefficients of the electrode members and the fluorescent tube, after cooling and fixing the rings, the electrode members, and the fluorescent tube, gaps occur, resulting in ineffective sealing of the fluorescent tube.
Accordingly, the present invention improves the sealing structure and provides a lamp having synthetic ceramic glass electrodes.